Norma is not the most widely performed work on the contemporary opera circuit. The music is unbeatable for its noble tunes and sauntering grandiosity, but the stately pace at which the action unfolds can produce turgid stagings in the wrong hands. It therefore seems natural that a handful of opera companies, from ETO to Deutsche Oper Berlin to the Mariinsky, have taken to performing Norma in concert version. Whilst tonight's rendition at the Macerata Opera Festival was clearly the full fat opera, staged as it was by two young Sicilian directors on the supersized platform on the Sferisterio, there was more than the whiff of a semi-staged reading. The music was first-rate but the production dangerously unengaged.

Overseeing the performance was Michele Gamba, who by good fortune has become the latest of a crop of up-and-coming Italian conductors. His big moment came duing La-Scala's March production of I due Foscari, a sudden illness felling bel canto wunderkind Michele Mariotti just moments before the curtain went up. One member of the cast recalled that Gamba had studied the work under Pappano, and the young conductor was called into action just eighteen minutes before the show was due to begin. "In gamba!", hailed the newspapers (on the ball!). Michele was an instant hit.

Tonight, there was panache in the way Gamba unfurled long melodies, coupled with requisite punch when we reached the temperature-raising battle cry "Guerra, Guerra!". For a conductor of such meek stature, Gamba exudes surprising authority, bringing off players with a swipe and reaching out far from the pit to coordinate dispersed chorus members. Most impressive was his sense of pacing. "Teneri figli" pulsated with pathos but never wallowed, while "Va crudele, al dio spietato" had strings scampering over an uncrumpled surface.

If all eyes were on Gamba then well-honed ears would have also been trained on Maria Jose Siri in the title role. The soprano opens La Scala's season with Madama Butterfly on 7 December - the most important event of the Italian operatic calendar - and some regarded this a taste of things to come. Puccini and Bellini are worlds apart, and Siri is not the world's most natural Bellinian. While there were lovely elements to "Casta diva", Siri's weighty voice limbered through trickling coloratura and pushed sharp on the climactic notes. Perhaps the colossal proportions of the Sferisterio had taken some getting used to: the singing settled as the evening progressed, with "Dormono entrambi!" especially fine as a liquid, brittle picture of sorrow.

In the role of Adalgisa, Sonia Ganassi has experience on her side. Her rich voice paired beautifully with Siri's, their celestial bond gorgeously conveyed in the intertwining duet "Mira o Norma". Tenor Rubens Pelizzari as Pollione was difficult to watch, a bundle of histrionic opera gestures that bordered on the comical. Considerably better was his singing, Pelizzari's bright, clarion voice possessive of a heroic quality.

Such a grand musical display was best enjoyed with eyes wide shut. The work of stage-director-duo Luigi Di Gangi and Ugo Giacomazzi was by turns unsightly, kitsch and opaque. The theme of characters ripping and wrapping shreds of fabric might have been intended to signify the bond between the Druids and their land. Toilet paper ribbons arranged on a dangling mesh did not make for the an enchanting moon, and the fil rouge (quite literally) that was hoisted high for much of the show was simply inexplicable. Here, the production team missed an opportunity to present a grand spectacle worthy of the Sferisterio's impressive surroundings. In the fine acoustic of the arena, however, musical quality alone made this visit to Macerata thoroughly worthwhile.